In order to improve the Signal-to-Interference-and-Noise Ratio (SINR) of received signals of User Equipments (UEs) at the edges of a cell, a Coordinated Multi-point Process (CoMP), in which multiple base stations provide a coordinated transmission service to one UE simultaneously, is introduced into a LTE-A (Long Term Evolution—Advanced) system, thereby forming an architecture with distributed multiple antennae, which can greatly improve the frequency spectrum efficiency of users at the edges of a cell.
However, compared with a single-cell transmission, a downstream coordinated multi-point transmission has the following problems:
In a coordinated multi-point transmission, signals transmitted by different base stations will have some phase differences when they arrive at a UE, while the UE can generally maintain time-frequency synchronization only with the current service base station. Since it is difficult to maintain synchronization with all the coordinated base stations, the signals will generally have phase noises when a UE end combines the received signals.